There is known a vehicle power transmission device that includes a first power transmission path transmitting power by engaging a first clutch and a dog clutch, and a second power transmission path transmitting power by engaging a second clutch each disposed between an engine and drive wheels in parallel. This corresponds to a power transmission device described in Patent Document 1. In Patent Document 1, it is described that the power transmission device having the configuration described above includes a fail-safe valve for preventing simultaneous engagement of the first clutch and the second clutch. When a total hydraulic pressure, which is sum of an output pressure from a C1 pressure electromagnetic valve controlling the hydraulic pressure of the first clutch and an output pressure from a C2 pressure electromagnetic valve controlling the hydraulic pressure of the second clutch, reaches a predetermined value or more the fail-safe valve is switched to a fail-safe spool position (state) to interrupt communication between an oil chamber of the first clutch and the C1 pressure electromagnetic valve.